One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Zone 4b you can estimate when it's the best time to plant asparagus by referring to the USDA zone info.

Planting Calendar for Asparagus

Frost tolerance for asparagus:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since asparagus are very cold tolerant you can plant them much earlier in the year than other plants that might not handle the cold.

The earliest that you can plant asparagus in Zone 4b is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant asparagus and expect a good harvest is probably August. If you wait any later than that and your asparagus may not have a chance to fully mature. If you are starting your asparagus indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Zone 4b the average date of last frost happens on May 15. You should expect an average low temperature of -25°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Zone 4b and it changes from year to year. Half of the time in Zone 4b you get a frost after May 15 so make sure that you are ready to cover your asparagus if you have a late frost.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.